Positive let-back mechanism for looms



Nov. 24, 1931. c. H. DRAPER 3,883

POSITIVE LET-BACK MECHANISM FOR LOOMS Filed Feb. 18, 1930 3 Sheets-Sheet 2 \nvenTor.

(More. H. Draper bYMWkM ATTys.

' Patented Nov. 24, 1931 stares;

oLARen. nmniaon nor-Enema mnssecnusnmms mana ement;

TION,, OF: HOP-EDALE,-, MASSALGHUSETJBS); AL CQBBORA'BIOM. 0E5 MAINE' BOSITIVE'. LET-BACK. Mechanism; Foe. Looms.

Application fild February 18, 1930;. Serial Reliance;

This invention relates to=the take up mech anism of a m and has' for its primary ob ject to provide meansactingto secureanac= curate, uniform, and positive amount'ofletback'or rotaryshift of the take-uproll when required inthe operation-of the loom to prevent a thin place'in' the" cloth being-woven.

The inventionis' concerned" wltha; loom provided with mechanism for efl'ecting a" change in the operation of the loom, such, feri example, as anautomatic replenishment of the running filling, upon the occurrence of a filling fault. For this purpose the loom is usually provided-with a filling fork which feels fortlie filling at each' ick and which, if the filling is'absent by reason ofbr'eakage or exhaustion of the running suppl y, acts" through suitable-mechanism automatically to replenish the supplyof: running' fillihgt When this occurs, one or more picks have not" been laid, although the action of the take-up has been'proceeding, and itis necessaryto reverse the rotation of thetake-up mechanism, or otherwise shift" the rotary posit-ion 'ot' the take-uprelatively to'its drive, or else a thin place; would occurin the cloth.

In the usual form of let-back mechanism, the take -up roll is momentarily disconnected fromits driving mechanism and thepull or tension on the clothacts to-efi'ect reverse rotation of the take up roll; Hence the amount oflet-back is moreor-lessindefiiiite and uncertain resulting, in imperfections in the cloth, especially inthe finer grades and with certain types of yarn; a

The present invention-provides a ccnstruc tion in which the connections fromtlie driving element to the takesup rollare permanently maintained both during the taking up and the lettingback movements and in which these connections: are positively, uniformly, and accurately operated to drivethe take-up rolliifn: the-one directiontoefiect'take up", and, when let-back is r'equired or a. thin place is to be prevented, to efi'ecta relative rotary shift of the'take-up roll: with respect tothe drivingjelement to decrease or'reverse the rotation ofthe take-uproll thus toeflect let-back; or to. prevent. the formation. ofa thin place in the cloth:

-When thetakemproll is being'driveir to eifect "In: the preferred fermof the" invention, these driving connections-includeaiplanetm'y or: differential system (if-gears ini which the revolublegears: are carried by ar housing:

take-up; thehous-ing-is held againstrotaticn and when let-back is required, thei housing is positively rotated. Thustlie'd'riv-ing connect tions are unbroken, ahe never disconnected in: the operation of the loom, and remain per manent throughout the operation of the-100111;.

1 The invention has as its furtherbbjecflto provide for the required positive, relative,

back ontoprevent a thin:place from themovea ment of the usual filling-fork: sli'de which'; when a filling fault occurs, is given a definite; positive; sliding movement and which is: in turn' impartedtothetakemprolll, i 7 These and other featuresbf: the invention will appear more fully from the aceompany ing descriptibnanddrawings andjwill helpert-icularly pointed out i in the cl'aims 1 The drawings illustrate so! much of ai-wellr known: type 015100111 as: is necesseny to: a :dim closure ot-the invention, together: Wlllhl 'a prefenred tor-m oh the invention: embodied therein. f 3 i i In the drawings: t a a Fig.1: is-a left-hand; side elev'ation pamui'ally broken awayo'ff the front end: oi'l the loomi Fig. 27is a front elevation of'the-iconstruey tion show-n in Figa J v Fig: 3, is: a detail 'ehieflly infivertical-cross section taken on= the. line of Fig: L.

Fig. 4 is a View in side elevation and pm tially in vertical cross. section on. thei lihe 4:4E0fFig-.'2-L' rotary shi-tt of'the take-up mu m efieaaee Fig." 5' -"is an enlarged detail pantiall'y verticallcross-section of the ratchet and operating mechanism therefon' shown: im Fig:.- 9/.

The loom'comprisestheiusual side'zfin of'whiohi a: portion: of the left-hand; frame 1 is shown! with the breast beam: QIeXtending therefrom" tothe, oppositeside frame; A 9

roll. 4' bygv frictional. engagement with. 1 0

take-up roll, A shaft is journalled in a bearing bracket 6 supported on the bottom of the frame and this shaft has journalled thereon a gear 7. A train of gearing which may be ofany suitable arrangement and indicated'generally at 8 extends from the gear 7 to the shaft 9 of the take-up rollso that, any rotation imparted to the gear 7 will in turn be positively and definitely imparted to the take-up roll. But it will be understood that the particular driving connections between the element 7 and the shaft 9 of the take-up 7 I roll may be of any suitable construction so long as they act to impart positively, directly,

and accurately the rotation :of the take-up roll'in either direction according to the direction ofrotation of the element 7.

[The shaft 5 has keyed thereto at 10 a worn wheel 11 and this worm wheel meshes with andwis. driven bya worm 12 keyed to a shaft 13 journalled in the'bearing bracket 6. and

extendingrearwardly in the loom frame and positively drivenfrom, one of the usual loom shafts. The shaft 5 has keyed thereon at .14 a driving element in the form of a bevelled gear 15; V

The elements I thus described, vby means of which, the driving element or bevelled gear 15 is given a positive rotation, may be of any suitable form and construction and specifically considered form no part of the present invention. 7

L i A driven element in the form of a bevelled gear 16 is journalled in axial alignment with the driving element or bevelled gear 15 and is preferably, j for that purpose, journalled on the shaft 5. This driven'e'lement 16 is the one which imparts a direct driving connection to the take-up roll and for that pur- V pose 'ispreferably formed rigid or integral with the gear 7 andthus acts through the train ofgearing 8 to drive the take-up roll.

A differential system of gearing is illustrated, including the bevelled gears 15 and 1 6, and comprises a cylindrical housing 17 I with one or more intermediate bevelled gears 18, herein shown as three in number, having their shafts 19 journalled radially'therein and so arranged that the bevelled gears 18 mesh with both of the bevelled gears 15 and 1 -.The outer cylindrical surface of the hous:

' ing 17 is formed to present a worm wheel 20 andthis worm wheel 20 meshes with a wormj21 secured to an auxiliary or transverse shaft 22 journalled in portions 23, of the bearing bracket 6. o

I It will thus be seen that under normal conditions with the shaft 22 immovable, the worm 21 will lock the housing 17 against rotation so that as the shaft 13 is rotated, a

1 direct positive drive'will be imparted from the driving element 15 through the inter mediate gears 18 to the driven element 16 and therefrom to the take-up roll to effect'takeup. The take-up roll will then be driven posi-' tively from the driven element at a fixed ratio of speed, depending upon the proportions of the driving connections therebetween. If now rotation be imparted to the auxiliary shaft 22, the housing 17 which isthe intermediate element of the differential gearing, will be positively rotated and such rotation will effect a relative rotary shift or change in angularrelation between the take up roll andthe driving element. Consequently, by rotating the auxiliary shaft 22 in the proper direction, the rotation of the take-up roll will actually decrease or be reversed according "to the relative speed of rotation of the shaft 22., This rotation of the auxiliary shaft 22 therefore shifts the rotary position of the take-up roll with respect to the driving element without in any way disturbing the permanency of the connections extending from the driving element to the take-up, roll. Thus the movement of the take-up roll to of fect let-back or to prevent a thin place is secured positively, accurately, and to an exact predetermined degree. If, when the aux- V iliary shaft 22 is rotated, the loom is stopped and the driving element 15" is thus held against rotation by the worm 12, then the movement imparted by the auxiliary shaft 22 to shift the relative rotary position of the" take-up roll with respect to the driving element is entirely devoted to a reversalofithe actual rotary movement of the take-up roll.

Thusin any event, when let-back is required or a thin place isto be prevented, the take-up rotation of the take-up roll is positively. counteracted to compensate for thelossflof picks due to a filling fault and to. prevent the formation of a thin place in the cloth.

In the preferred form of the invention, rotation is imparted to the auxiliary shaft 22 thus to effect let-back or prevent a thin place, upon the occurrence of a filling fault, by connections positively and accurately operated mer 28 of the usual type is fulcrumed at 29 in the 100111 frame a-nd at-itsrearward end carries a. follower 3O riding on acam 31 on the camshaft 32 of the loom. If the filling is properly laid in the shed, it engages: the tines 26 on the-beat-up and the fillingfork is rocked, raising the looped end 27. If the filling is broken or exhausted .or otherwise in fault, the fork 26 is not rocked and'the loopedend'27 catcheson the end of the weft hammer 28 so that as the 'cam 31 revolves, the

filling fork slide: is given a positive, accurate, and definite forwardmovement and, at the same time, through connections fannhar to those skilled in. the art, the; desiredchange is effected in the operation. of the loom. suchas the automatic replenishment of' the running filling or such; as the stop-ping ofthe loom; Itis this-movcn'ient of thefilling fork slide, or aportion of this movement, that is here preferably utilized for rotating. the anailiary shaft 22. to effect let-back or prevent a thin. place.

A ratchet wheel 33 is. keyed. at 34 to the shaft A pawl carrier in the form of a sector-shaped casing 35 isjournalled onthe shaft 22 surrounding the ratchet-wheel and haspivoted theretoat 36 a: pawl 37 coop crating: with the ratchet wheel 83 and nor mally held in engagement therewith by a helical spring 38 seated in a pocket in an extension 39. of the pawl andabuttingthe outer surface of the carriercasing 35; The pawl carrier casing; 35 is oscillated through suitable adjustable connections extending upward therefrom by the filling fork slide,

The connections for thus operating the pawl carrier from the filling fork slide are illustrated in a simple and preferred form. A bell crank lever is fulcrumed at 40 in a bracket 41 bolted to the breast beam. The upstanding arm of thisbelli crank. lever is in the form of a plate 42 which extends at the front of the end. of the fillingfork slide; This arm is yieldingly drawn toward the filling forkslide-by a. spring 43 connected at theferward end to astud: 44 extending from the arm 42 and at the rearward. end'to astud 45 on the breast beam. A set screw 46in the arm. 42 adj ustably determines the rearward movement of the bell crank lever under the influence of the spring 43 and thus the point in I the forward movement of the filling, fork.

slide when the filling fork slide will engage with the bell crank lever andzbe in' to impart a positive forward movement thereto. The

forwardly extending arm 47 of thebell crank,

lever has adjustably connected thereto a link 48, this adjustment being effected by placing a. stud 49 in one or the otherof the holes 50 in the arm 47. The lower end ofthe link 48 is pivoted at 51 in a bifurcated arm 52 journalled on a shaft 53 which may bethe usual starter rod' found on looms of this type. A two-part link 5.4 55. adjust-ably connected together by the bolt 56 is pivotally connected at its upper end at 57 to the arm 52 and its lower end at 58 to the pawl carrier casing 35.

Such a means as that described thus causes let-back to take place or a thinplace to be prevented by a positive, accurate, and predetermined movement without disturbing the permanency of the connections. which extend from the driving element. to the take-up roll.

Furthermore, such; a construction provides means by which the extent or degree: of the; decrease inthe rotation. or. the reverse: rota tionofi the take-uprollamay bevaried as re quired-. H

1 .When aifillingzfault occurs andia-lchangein: the operation; of the tlO0IIl,,SU.Ch: as a replenishment-of the filling, takesplace: Wifihi the loonr continuing to run, the cam; 31 actsthrough the. wefthammer to: give; a" definite and positive .degreeof movement to" the: Weft fork.

slide. By theadjustinent of'the, set screw 46, the bellcrank lever 42,457 isadjusted.in-;pos r-- tion so,- that the; entire movement, or any, desired portionioftheientiremovement, of the slideiwil l be positively impartedtheneto: By. the a-dfiustmentot the upper-pivotal; point49' of the link. 48; into one of the holes. 50,, the.

amount of movement imparted: to they bellcrank. lever is imparted: in apredetermined: amount through; the connections described: to the pawl carrier As aresult, the: ratchet 33 is moved and therewith the worm 21 to rotate the. housing 1-7 and; consequently, as

described, the rotary'angnlar position. ofthe ta-ke-up roll is shifted relatively-to the driving element without: disturbing the-permaenent connectionstherebetween. This may be simply, a decrease in .theactualrotat'ion of thetake-up. roll or an actual..reversalof'rota tion. But in any eventa thin place in the cloth'is prevented. v

If, when the filling fault occurs,..the loom is stopped, then! the driving element1'5 is held.

. against rotation by theworm 1-2: and the rota tion of the-housing; 1.7 i acts positively to effect a reverse rotation ofthe take-up roll to effect the required let-back. Y

The shaft 5 isprovided at the-.endswith- V collars 59 and GO-seeured tl'IQIGlZOtlO'hOldE the parts in proper. position. A hand, wheeL 6L is mounted. on the end of the; auxiliary shaft 22,,thus enabling the auxiliary Sha-ftTtO be turned manually when: it is desired to adjust or set the take-up roll in proper position A friction='brake is also provided on .the auxiliary shaft 22 to prevent any lost motion,

overthrow or. slippage of the. connections.v This is shown as. comprising a drum. (32.- secured to theshaft .22 and a bifurcated or split collar encircling the drum, a stud-66- extending from one of'the bearing portions 23 ofthebracketfi and entering. a slot 67 in the collar toi prevent rotary movement, thereof,

LA loom. comprising a take-up ro1l,,a-

driving; element, a permanent i positive.- drive ing connection from the drivingelement to thetake-up roll actingto rotate the take-up rollat a fixed ratio of speed with respect to the driving element to effect take-up, and means acting'upon the occurrence ofa filling fault toshift the angular relation of the takeup roll with respect to the driving element to prevent athin place in the cloth.

- 2. A loom comprising a take-up roll, a driving element, a permanent positive driving connection from the driving element to the take-up roll actin to rotate the takeup roll at a fixed ratio of speed with respect to the driving element to effect take-up, means acting upon the occurrence of a filling fault positively to rotate the take-up roll with respect to the driving element to decrease or reverse its taking up movement to a predetermined extent thus to effect let-back or prevent a thin place in the cloth.

3. A loom comprising a take-up roll, means for driving the take-up roll to effect take-up,

means acting upon the'occurrence of a filling fault'to effect a change in-the operation of the loom, and means acting thereupon positively and without disconnection of the takeup roll from its driving means to counteract to a predetermined degreethe-take-uprotation of'the take-up rollto compensate for the loss of picks'caused by said fault;

4. A loom comprising a take-up roll, adriving element, a differential system of" gearing between the driving element and the take-up roll for driving the latter from the former to-efl'ect take-up, means acting upon the occurrence of a filling fault to efi'ect a change in the operation of the loom, and means acting thereupon positively to rotate bodily and to a'predetermined extent the intermediate element of the differential gearing-to shift the rotary position of the take-up roll with respect to the driving element in a direction to effect'let-back or prevent 'a' thin place in the cloth.

5I'A loom comprising a shaft, means for positively driving the shaft, a driving gear secured to the shaft, a driven gear journalled in axial alignment with the shaft, a take-up roll, a gearing connection between the takeup roll and the driven gear, a housing, an

' intermediate gear journalled in the housing secured to the shaft, a driven gearjournalled in axial alignmentwiththe shaft, a take-up roll, a gearing connection between the takeup roll and the driven gear, a housing, an intermediate gear ournalled 1n the housing and meshing with the driving and driven gears, an auxiliary shaft extending transversely of the housing, a worm on the auxiliary shaft, a worm wheel'on the housing cooperating with the said worm, the said auxiliary shaft normally acting to hold the housing \gainst rotation and thus enable the take-up oil to be driven positively to effect take-up, and means actuated when let-back is required to rotate the'auxiliary shaft a predetermined degree thereby to effect positively the desired 7 amount of let-back;

7. A loom comprising the construction defined in claim 5, together with a friction brakesecured to the loom frame and engaging the auxiliary shaft to prevent undesired move ment thereof. r

8. A loom comprising the construction defined in claimfi, together with a hand wheel secured to'the auxiliary'shaft thus to enable the take-up roll to be turned manually in either direction. 7

9. A loom comprising a shaft, means for positively driving the Shftit, a driving gear" secured to the shaft, a driven gear journalled in axial alignment wit the shaft, a takeaip roll, gearing connection between the'takeup roll and the driven gear, a housing, an intermediate gear journalled in the housing and meshing with the driving and, driven,

,a eara'an auxiliary shaft, a gearing connection between the auxiliary shaft and housing,

the said auxiliary shaft normally acting to hold the housing against rotation and thus enable the take-up roll to be driven positively to effect take-up, a filling fork, a filling fork slide, means for imparting a definite, positive, sliding movement to the slide upon indication of filling absence by the fork, and means actuated by the said movement of the slide to rotate the auxiliary shaft a'predeten mined degree thereby to effect positively the desired amount of let-back.

10, A loom comprising a shaft, means for positively driving the shaft, a driving gear secured to the shaft, a driven gear ournalled in axialalignment with the shaft, a take-up roll, a g'earin connection between the takeup roll and the driven gear, a housin an intermediate gear journalled in the housing and meshing with the driving and driven an auxiliary shaft, a gearing connection between the-auxiliary shaft and housing, the said auxiliary shaft normally acting to hold the housing against rotation and thus en able the take-up roll to be driven positively to effect take-up, a filling fork, a filling fork slide, means for imparting a definite, positive, sliding movement to the slide upon indication of filling absence by the fork, and a pawl and ratchet connection between the slide and the auxiliary shaft acting upon the said movement of the slide to rotate the auxiliary shaft thereby to efiect positively the desired amount of let-back. V V

11. A loom comprising a take-up roll, means for driving the take-up roll to effect take-up, means acting to effect a change in the occurrence of a filling fault, and means acting upon the stoppage of the loom, and without disconnecting from the take-up roll the means for driving it, to give a definite predetermined amount of positive reverse rotation to the take-up roll to effect let-back.

13. A take-up and let-back mechanism for looms comprising a driving element, a takeup roll, a train of permanent connections between said driving element and roll, and means for holding one of said connections against movement and to permit the rotation of the take-up roll to effect take-up when take-up is required and for moving the said connection to decrease or reverse the rotation of the take-up roll thereby to effect letback or prevent a thin place as required.

14. A take-up and let-back mechanism forlooms comprising a driving element, a takeup roll, a train of permanent connections between said driving element and roll, one of said connections being rotatably mounted and acting when held against rotation to permit the driving element to rotate the takeup roll to effect take-up, and means acting upon the occurrence of a filling fault to rotate the said connection to decrease or reverse the rotation of the take-up roll thereby to effect let-back or prevent a thin place.

15. A take-up and let-back mechanism for looms comprising a driving element, a takeup roll, a train of permanent connections between said driving element and roll acting to rotate the roll to effect take-up and means for positively moving one of said connections, when the driving element is at rest, to reverse the rotation of the take-up roll thereby to efiect let-back.

16. A take-up and let-back mechanism for looms comprising a driving element, a takeup roll, a train of permanent connections between said driving element and roll acting to rotate the roll to effect take-up and means, actuated upon the occurrence of a filling fault, to move one of said connections to de crease or reverse the rotation ofthe take-up roll to effect let-back or prevent a thin place.

17 A take-up and let-back mechanism for looms comprising a take-up roll, means for positively rotating the take-up roll either in a direction to effect take-up or in the reverse direction to effect let-back, the said means including an element held stationary during rotation of the take-up roll to effect take-up and moved to eflect that rotation of the take-up roll required to effect let-back.

18. A loom comprising a take-up roll, means for driving the take-up roll to effect take-up, said means permanently connected With the take-up roll, a filling fork, a filling fork slide, means for imparting a definite,

positive, sliding movement to the slide upon 7 indication of filling absence by, thefork, and connections between the slide and the takeup roll driving means acting upon the said movement of the slide to give positively a definite predetermined amount of rotary shift of the take-up roll relatively to its driving means to prevent a thin place in the cloth.

In testimony whereof, I have signed my name to this specification. v

CLARE H. DRAPER. 

